Rubber composition and method of preserving rubber



Patented July 4, 1933 unirat sures PATENTO C MARION Q. REED, SOUTH GHARLESTON, WEST VIRGINIA, ASSIGNOR 'i'O 'JJIHIEv 13. IF; 'GOODRICH COEJIPANY, OF NEW YORK, N. 'Y., A CORPOR TION OE NE'W YORK" qnumsnn COMPOSITION AND METHOD or rnnsnnvrne' RUBBER No Drawing. Original application filed November 4, 1929, Serial 110,404,868.

filed'April 27, 1932.

This invention relates to the art of preserving rubber, either in the vulcanized .or un- This invention consists in treatin rubberwith a member of a new class of age-resisters, the said class comprlsing secondary amines,

one of the substituents of which is a monovalent aliphatic hydrocarbon group while the other is an aromatic greup containing more than one aromatic ring." The aliphatic group may be any straight orbranched chain aliphatic hydrocarbon group, or alicyclic group, and may even contain aromatic rings remote from the point of attachment as in the benzyl group. The aromatic group may contain two or morev aromatic rings, conjugated, adjacent or indirectly joined one to another. Thus, the class includes such substances as: methyl-alpha naphthylamine, methyl-beta-naphthylamine, meth yl-anthra cylamine, methylamino-biphenyl, methylamino-diphenylmethane, methylamino-diphe nyl ether, p-methylamino-diphenylamine, N'

methyl-N-betaenaphthyl-p-phenylene diamine, prmethylamino-diphenyl-p-phenylene-diamine,. 1.-methylamino-4-naphthol, pmethylamino-p-hydroXy-diphenyl 7 ether, p,p di-methylamino-diphenylamine, and the corresponding ethyl, propyl, butyl, amyl,

heptyh'and other alkyl derivatives, as well as similar compounds containing other substituent groups such as the cyclopentyl cyclohexyl, and benzyl and phenyl-ethyl groups, which, although not strictly aliphatic in nature, undergo the characteristic reactions of and confer upon their compounds essentially the same properties as purely aliphatic groups; it being understood that the above-named. com- Divided and this application Serial No. 607,888.

containing: blended plantation rubbers 100 parts by weight, sulfur 5.5parts, zinc oxide parts, gas black 40 parts, mineral rubber 10 parts, palm oil 5iparts, hexamethylene tetramine 0.75 parts, and methyl alpha-naphthylamine 1;. 90parts. ,The composition was thoroughlymixed,and vulcanized ina press for minutes at 145 C. (294 ,to produce an optimum cure. The rate of aging of the vulcanized composition was determined by measuring its tensile strength andelongation before and after aging. The accelerated aging test was carried out in the .Geer aging oven, in which samples were maintained at a temperature of 70C. (158 F.) in a constantly renewed stream of air, the results being recorded in the following table, in which T indicates ultimate tensile. strength in pounds per sq. inch and E indicates ultimate elongationin per cent. of original length:

Aging tests of methyl-al )ha-aaphthylcmine Before After 2 i After 5 After 7 aging days days days A similar composition without the methyl: alpha-naphthylamine deteriorated approximately twice as much in the same time.

Example 2.A rubber composition similar to that specified .lIl'EXflDlPlQ 1 above but without the. vmethyl-alpha-naphthylamine was divided into 5 portions, one of which was used as a control. To the others were added respectively 0.95 parts (0.5% of the weight Aging tests of alkyZ-alpha-naphthylammes After 48 Before i g hours in aging ays e the Bierer- Geer oven Davis bomb Age-resister (0.5%)

None (control) 3624 675 1792 440 839 362 Ethyl-alpha-naphthylamine 3588 G73 2412 473 2387 570 2- isoamyl alpha naphthylamine 3444 703 2952 640 2208 603 Cyclohexyl alpha naphthylamine 3471 677 1945 520 1438 500 Benzyl -alpha-n a p h t h v]- amine 3648 670 2680 573 2155 583 From the examples given above it is evident that secondary amines of the above-described class, namely those possessing the general type formula where R, is an alkyl group and R is an aryl group containing at least two aromatic rings, are extremely effective in retarding the deterioration which rubber normally undergoes upon aging.

Obviously, the practice of this invention is not limited to the specific compositions given above, such compositions being merely illustrative of one manner of employing the age-resisters of this invention. The proportions of the constituents may be varied, or other substances may be substituted therefor, since this invention is applicable to pure rubber or rubber compositions of the most varied nature. The age-resisters may also be applied to unvulcanized or vulcanized rubher with good eflect on the age-resisting properties of the rubber, such as by applying them to the surface of the rubber, as for example in solution, or in the form of a paste or emulsion.

It is to be understood that the term treating as employed in the appended claims is used in a generic sense to include either the incorporation of the age-resisters into the rubber by milling or similar process, or their addition to the rubber latex before its coagulation, or to the application thereof to the surface of a mass of crude or vulcanized rubber. The term rubber is likewise employed in the claims in a generic sense to include caoutchouc, whether natural or synthetic,

reclaimed rubber, balata, gutta percha, rubber isomers and like products, whether or not admixed with fillers, pigments, vulcanizing or accelerating agents. The term aliphatic, unless otherwise limited, is to be understood as including all substituent groups which confer the characteristic properties of alphatic compounds on their derivatives, as opposed to aromatic groups which confer different and distinctly aromatic properties on their derivatives, and particularly as including all groups hereinbefore referred to as aliphatic in nature.

This application is a division of my copending application Serial No. 404,868 filed November 4, 1929.

While I have herein disclosed certain preferred manners of performing my invention, I do not thereby desire or intend to limit myself solely thereto, for, as hitherto stated, the precise proportions of the materials utilized may be varied and other materials havingequivalent chemical properties may be employed if desired without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. The method of preserving rubber which comprises treating rubber with a substance of the general formula where R is a monovalent aliphatic hydrocarbon group and R is an aromatic group containing at least two distinct aromatic rings. 2. The method of preserving rubber which comprises treating rubber with a substance of the general formulaa ar-R:

where R is an alkyl group and R is an aromatic group containing at least two distinct aromatic rings.

3. The method of preserving rubber which comprises treating rubber with a substance of the general formula where R is a monovalent aliphatic hydrocarbon group and R is an aromatic hydrocarbon group containing at least two distinct aromatic rings.

4. The method of preserving rubber which comprises treating rubber with a substance of the general formula i R -NR where R is an alkyl group and R is an aromatic hydrocarbon group containing at least two distinct aromatic rings.

5. The method of preserving rubber which alt) comprises treating rubber with a substance of the general formula R1NR2 where R is a monovalentaliphatic hydrocar 7 ben group and B is an aryl group containing two distinct but directly connected aromatic rings. The method ofpreservin'g rubber which comprises treating rubber with a substance of the general formula R -N-R2 1 v where R is an alkyl group and R is an ary group containing twofldistinct but directly connected aromatic rings.

7. The method of preserving rubber which comprises treat-mg rubber with a substance of the general formula where R is a monovalent aliphatic hydrocarbon group and R is a biphenyl group.

8. The method of preserving rubber which comprises treating rubber with a monoallryl aminobiphenyl.

9. The method of preserving rubber which comprises treating rubber with a substance of the general formula 1].. The method of preserving rubber which comprises treating rubber I ith a substance of the general formula "i R'1NR2 where R is a straight chain alkyl group and R is a biphenyl group.

12. The method of preserving rubber which comprises treating rubber with ethylamino biphenyl.

13 The method of preserving rubber which comprises treating rubber with a substance of the general formula where R is a monovalent aliphatichydrocarbon group R 1s an aromatic group containing two distinctaromatic rings connected to an aliphatic nucleus. y i

14:. The method of preserving rubber which comprises treating rubber with a substance of the general formula t 7 R1NVR2 where R is an alkyl-group and R is a diphenyl methane group.

15. The method of preserving rubber which comprises treating rubber with a substance of the general formula swi s.

where R is a butyl group and R is an aromatic group containing two distinct aromatic rings 16. The method of preserving rubber which 35 comprises treating rubber with n-butylamino diphenylmethane.

17. The method of preserving rubber-which comprises treating rubber with a substance of the general formula 1-! R1N B2 V s where R is a monovalent aliphatic hydrocarbon group and R is an aromatic group 0011- taming two distmct aromat1c rings attached to a secondary amino nitrogen.

18. The method of preserving rubber WlllCh' comprises treating rubber with a substance of the general formula 0 rr R N-Rz y where R is an alkyl group and B is anaromatic group consisting of two aromatic rings attached to a secondarvammo mtrogen.

19. The method of preservlng rubber which comprises treating rubber wlth a substance of the general formula I v R1-N-R2 where R is a branched chain alkyl group and R is an aromatlc group contaming two distinct aromatic rings.

20. The method .of preserving rubber 5 which comprises treating rubber with a substance of the general formula where R is an isopropyl group and R is an aromatic group containing two distinct aromatic rings.

21. The method of preserving rubber which comprises treating rubber with an iso- 1 propylamino diarylamine.

22. The method of preserving rubber which comprises'treating rubber with p-isoproylamino diphenylamine.

23. The method of preserving rubber which comprises vulcanizing a mixture of rubber, sulphur, an active organic accelerator, and a substance of the general formula H V R1-A-R2 where R is monovalent aliphatic hydrocarbon group and R is an aromatic group contaming at least two distinct aromatic rlngs.

24. The method of preserving rubber which comprises vulcanizing a mixture of rubber, sulphur, an active organlc accelerator, and a substance of the general formula IiI Ih-N-R where R is an alkyl group and R is an aryl hydrocarbon group contalning two distmct aromatic rings.

25. The method of preservlng rubber which comprises Vulcamzmg a mixture of rubber, sulphur, an active organic accelerator and a substance of the general formula 1 u n-n2 where R is an alkyl group and R is a diarylamlne group.

26. A composition comprising rubber and a substance of the general formula where R is a monovalent aliphatic hydrocarbon group and R is an aromatic group containing at least two distinct aromatic rings.

27. A composition comprising rubber and a substance of the general formula where R is an alkyl group and R is an aromatic group containing two distinct aromatic rmgs.

28. A composition comprising rubber and a substance of the general formula f R N R2 where R is a straight chain alkyl group and R is an aromatic group containing two distinct aromatic rlngs.

29. A composition comprising rubber and a substance of the general formula H R 1 IR where R is an ethyl group and R is an aromatic group containing two distinct aromatic rings.

30. A composition comprising rubber and a substance of the general formula H R 1 IR-;

where R is a butyl group and R is an aromatic group containing two distinct aromatic rings.

31. A composition comprising rubber and a substance of the general formula where R is a branched chain alkyl group and R is an aromatic group containing two distinct aromatic rings.

32. A composition comprising rubber and a substance of the general formula 11 R1IIWR- where R is an alkyl group and R is an aromatie group containing two distinct aromatic rings attached to a secondary amino nitrogen. i

35. A compositioncomprising rubber and an alkylamino diphenylamine.

In witness whereof I have hereunto set my hand. this 19th day of April, 1932.

MARION C. REED. 

